Field of the Invention
The present invention relates to a ratchet driving mechanism, especially to a ratchet driving mechanism for a hand tool.
Description of Related Art
A conventional screwdriver is composed of a rod member being combined with a handgrip and used for rotating a fasten member (such as a screw) for the purpose of combination. For providing more conveniences in use, various types of ratchet driving mechanisms have been developed for controlling the direction in which the screwdriver is driven, so the fasten member (such as a screw) is able to be easily rotated.
However, the ratchet driving mechanisms are all provided with two thin plate members for being engaged with a gear composed of a plurality of ratchet teeth, the thin plate member only utilizes an edge for being mutually engaged with the ratchet teeth, so the thin plate member is unable to sustain a larger torque, in other words the user cannot apply a large torque or the plate member would be very likely to be damaged. During the plate member being engaged with the ratchet teeth, a position member and an adjustment ring are provided for the purpose of position limiting; when a torque is applied for rotation, the adjustment ring is very likely to be recovered or slid due to the friction force, so the position member would be released from a position hole thereby causing imprecise positioning, and the screwdriver is unable to be normally operated.